Transradial coronary angiography DAVID HILDICK-SMITH T he transradial approach to coronary angiography was first considered to be a serious possibility in 1989. Gradual miniaturisation of equipment, coupled with the continuing desire to reduce patient discomfort and procedural risks, allowed the introduction of 6 French (6F) catheters. At 2 mm diameter, these fit without difficulty into most radial arteries. After Campeau experimented with this approach, others saw the potential, both for angiography and for angioplasty. From the diagnostic point of view, a simple transfemoral catheterisation is quick, uncomplicated, requires limited bed rest afterwards and can be accomplished with ease on a day-case basis in most patients. An arm approach is required in some patients because of difficulties with peripheral vascular disease, haemostasis or an inability to lie flat. These patients have formed the focus of our transradial diagnostic programme at Papworth Hospital. the transfemoral and transradial routes for diagnostic coronary angiography. 1 This study gave clear results: even allowing for the learning curve, the transradial route took longer, was more com-plicated, and resulted in a greater degree of pain in a significant proportion of patients. We therefore decided that the radial route should be reserved for patients in whom there is a relative con-traindication to the femoral approach, and we have continued with this policy ever since, though other authors have suggested that the transradial route is preferred by patients for diagnostic as well as interventional work. 2 We then compared the transradial route with the brachial cut-down procedure in a randomised study of 100 patients with con-traindications to the femoral approach. (~5%) and therapeutic anticoagulation (~10%). Diagnostic coronary angiography from the radial artery begins with a modi-fied Allen test to assess dual palmar arch circulation.